Textures appears in Blender Render but missing in Cycles Render
Blender Cycles and Blender Internal are two completely independent rendering systems with different settings and material definitions.

Your UV Maps did not disappear, you just have to recreate your materials using the Cycles material nodes system.

Have in mind that even after recreating them, the Blender viewport does not support displaying material previews for cycles, only basic preview of image based textures, so you will only get to see them upon rendering or on interactive viewport render.